The most traditional design of vaned rotors, vital in particular in turbojet engines, consists of separately producing the disk of the rotor and the vanes and of assembling the latter on the disk by engaging the feet of the vanes on grooves of the disk. In fact, it is often advantageous to produce the vanes separately which are incurved parts whose shape is often complicated to embody.
Added to this is the difficulty of installing platforms between the vanes so as have the disk bordered by a circular smooth surface whose function is to delimit the gas flow vein, as these platforms are often elements mounted between the top side and bottom side of the adjacent vanes, which allows plays (i.e. clearances) to exist which destroy the continuity of the surface of the vein and which need to be to reduced as far as possible so as to avoid compromising the quality of the flow.
One current conception consists of producing the platform segments from a block with the vanes. Its details appear in a large number of patents and has the advantage of the fact that the platform segments meet together at mid distance from the vanes by straight joining points easy to fill up by a sealing lining. The drawback is that the platforms, whose extension is approximately perpendicular to that of the vanes, are complicated to produce.
Moreover, it is advantageous to lighten the rotor by producing these elements made of a composite material less exposed to forces, this possibly concerning the platforms and thus requiring that they be separated from the vanes.